Yes, you can put the triton 2 on the ego one mega battery. Just bare in mind that the ego one mega sets it's wattage according to the coil you're using. So if you're using a 0.5 ohm coil, you'll get around 26-33 watts. Wattage will drop off when voltage gets lower.
It's better to talk about these things in terms of voltage, as it's more relevant to the battery.
Now assuming the battery is fully charged at 4.2v with no battery drop you'll be getting 35.28W, (
Ohm's law | Steam Engine | free vaping calculators feel free to use this calculator to work out wattages) The triton is a very good tank from what I've heard, but so is the ego one tank in my experience, how did your friend break the tank? If it was just the coil he could easily (and cheap compared to a new tank) get some new coils. Any standard tank with a 510 pin (not ego) should fit perfectly on the ego one mega, but you may want to consider the diameter of the tank so there's no overhang but that's purely cosmetic. As long as the battery can support the resistance of the coil in the tank and it has a 510, there should be no problem, there is a vast selection of tanks available, it really depends on your friends style of vaping.
